Silicious valves are fairly well known, and numerous publications exist dealing with their structure and various manufacturing techniques. For example, U.S. Pat. No. 5,082,242 teaches an electronic micro-valve which has an integral structure made on one piece of silicon and is a flow through valve with an inlet and an outlet on opposite sides of the silicon wafer. The aperture for flow through the silicon wafer is opened and closed by a movable closure member that merely covers the-aperture for flow.
In the article "Electrically Activated, Normally Closed Diaphragm Valves" by H. Jerman (91CH2817-5/91 IEEE), there is a disclosure as to electrically activated, normally closed diaphragm valves that have been fabricated using heated bimetallic diaphragms to provide the operating force. FIG. 1 in the document discloses a boss which completely covers the valve seat, thereby preventing flow to the outlet.
In the article entitled "Smallest Dead Volume Microvalves For Integrated Chemical Analyzing Systems" by S. Shoji, B. Van der Schoot, N. de Rooij and M. Esashi (91CH2817-5/91 IEEE), there is a discussion with respect to normally open and normally closed microvalves and a three-way microvalve. The drawings depict a ridge in a silicious substrate which contacts a polymer membrane, thereby controlling flow through the inlet and outlet.
Numerous other references pertain to micro machine valves and are listed as follows. U.S. Pat. Nos. 4,581,624; 4,647,013; 4,657,621; 4,670,092; 4,756,508; 4,768,751; 4,826,131; 4,869,282; 4,966,646; 5,029,805; 5,065,978; 5,082,242; and the article entitled "Variable-Flow Micro-Valve Structure Fabricated With Silicon Fusion Bonding" by F. Pourahmadi, L. Christel, K. Peterson, J. Mallon and J. Bryzek (CH2783-9/90 IEEE).
It is an object of the present invention to obtain silicious micro-valves which have a movable spool and/or valve seat which permits a complete alignment with the 111 planes of the spool and the conforming seat.
It is another object of the present invention to obtain a conformed spool and valve seat which (i) permits sharp edge orifice controls to thereby obtain improved flow viscosity effects and (ii) has improved sensitivity of the valve and thereby improved valve performance.